Bis(aryl)acenaphthenequinonediimine Substituent Effect on the Properties and Coordination Environment of Ligands and Their Bis‐Chelate Ag^I Complexes

Abstract

The reaction of a series of Ar-BIAN ligands H 4 ) with AgNO 3 results in the formation of the corresponding bis-chelate complexes. Substituent groups on the aryl rings seem to offer tunability of the electronic properties of the diimines, also affecting the metal coordination environment through the mono-coordination or chelation of the nitrate anion as promoted by the sub-[a] Aristotle

Tuning the Electronic Properties of Homoleptic Silver(I) bis-BIAN Complexes towards Efficient Electrocatalytic CO2 Reduction

“…All the Ag-N bond lengths of Ag4 that crystallized in the orthorhombic space group (Ccca) were equivalent with 2.327(2) Å. Additionally, this extended to the BIAN C=N and imine C-C bonds with bond lengths of 1.261(4) Å and 1.527(6) Å, respectively. These values were consistent with reported bond lengths of neutral BIAN ligands, further verifying the general structure that was depicted in Scheme 1 [37][38][39][45][46][47]. They were nearly identical with the values reported for the molecular structure of the free ligand L4 [48], illustrating the absence of any particularly strong synergistic interaction from the Ag center to the BIAN, such as extensive π-back bonding, which was in agreement with the data obtained from UV-vis spectroscopy (vide supra).…”

“…UV-vis spectroscopy revealed that, despite metalation, no intense long-wavelength metal-to-ligand charge-transfer (MLCT) processes occurred in the prepared complexes Ag1-Ag6 and, predominantly, the intra-ligand centered π-π* and n-π* transitions of the aryl, acenaphthene and imine moieties were observed in the acetonitrile solutions [39,42,43]. Nevertheless, these absorptions bands were altered upon coordination to a varying degree, indicating at least some participation of the Ag orbitals with the aforementioned excitations [38]. The UV-vis absorption maxima and corresponding logarithmic extinction coefficients are listed in Table 1.…”

“…Additionally, only a few reports on silver BIAN complexes have been published in the literature, almost exclusively focusing on their synthesis and characterization with none of the studied compounds being utilized for catalytic applications of any sort [37][38][39].…”

Trapping of Ag+ into a Perfect Six-Coordinated Environment: Structural Analysis, Quantum Chemical Calculations and Electrochemistry

“…Many complexes of late transition metals with BIANs have been reported [ 36 , 37 , 38 , 39 , 40 , 41 ]. However, Ag complexes with BIANs remain scarcely explored: There are only seven structurally characterized examples of Ag-BIAN complexes [ 42 , 43 , 44 , 45 ]. The first mention is found in the report by Rosa and co-workers, who reported the preparation, spectroscopic, and computational studies of [Ag(dpp-bian) 2 ]BF 4 and [Ag(tmp-bian) 2 ]BF 4 [ 42 ].…”

The structural and electronic impact on the photophysical and biological properties of a series of CuI and AgI complexes with triphenylphosphine and pyrimidine-type thiones

“…The divergent coordination behavior of silver, especially underlined by the formation of a trigonal planar geometry, agrees with its known high lability demonstrated in a variety of disproportionation and ligand scrambling reactions. 46 By inspecting the NBO atomic charges of the Ag I -pymtH related systems (Table S7, ESI †), it becomes obvious that upon coordination there is a charge shift from the sulfur atom (À0.16 charge units for the free thione) and the two phosphorus atoms (+0.91 charge units in the free triphenylphosphine) towards the metal center (À0.13 charge units for the S and +0.95 charge units for the P atoms in the complex) with the latter aquiring a charge of +0.29 units in the [Ag(PPh 3 ) 2 (pymtH)] + (7) complex. An analogous diminishing of electronic charge occurs for the iminic nitrogen atom of the thione upon coordination (from À0.56 in the free thione to À0.54 in the Ag I -complex) while an opposite sign charge variation of ca.…”